The hypothesis of this application is that focal areas of hypoxic placenta produce inflammatory cytokines (TNF-alpha and beta, IL-1 alpha and beta) which in turn participate in the vascular alterations resulting in preeclampsia during pregnancy. In the first aim, the investigator will determine if normal pregnant and preeclamptic placental villous and decidual explants will express cytokines when subjected to hypoxia. In aim 2, they will determine if HIF-1 contributes to the hypoxia-inducible cytokine expression by placental tissues. In aim 3, they will determine if cytokine levels and cytokine mRNA are increased in placental tissues from women with preeclampsia compared to normal pregnant women. In aim 4, they will search for specific markers of focal areas of placental hypoxia. In aim 5, they will investigate whether endogenous NO, CO, and/or cGMP regulate the expression of placental cytokines.